Okay, after taking way too much time hemming and hawing, I've narrowed it down to Maximo Nivel or ITTO, both in Cuzco. MN would be slightly cheaper, but I've heard some weird stuff about the hiring practices of their local English school (which may/may not reflect on the quality of their TEFL program, or even be true). Also, MN's customer service has been a bit more on-the-ball than ITTO's, which is a silly thing to judge a school by but, hey, first impressions...

If you go with ITTO in Cusco, you will be sorely disappointed, as they are just a middleman who finds clients for Maximo Nivel and makes a comission off of it. So whether you choose ITTO or Maximo Nivel, you will still be doing the exact same TEFL program. Just a heads up.

Also, I would be interested to know what exactly is in the Ken Jones interview, as I know him personally and am curious what light he casts himself in